Light-sensitive material

ABSTRACT

A LIGHT-SECSITVE MATERIAL COMPRISING A SILVER HALIDE EMULSION LAYER AND CONTAINING A MERCURY(II) CHELATE OF A (POLY) AMINO-(POLY)CARBOXYLIC ACID IN THE FORM OF THE ACID OR A WATER-SOLUBLE SALT IS DESCRIBED. THE CHELATC EXERSTS A STABILIZING AND FOG-INHIBITING ACTION UPON THE LIGHTSENSITIVE MATERIAL WITHOUT CAUSING APPRECIABLE DESENSITIZATION.

United States Patent 01 lice 3,595,662 Patented July 27, 1971 3,595,662 LIGHT-SENSITIVE MATERIAL Jozef Frans Willems, Wilrijk, and Robreeht Julius Thiers, Brasschaat, Belgium, assignors to Gevaert-Agfa N.V., Mortsel, Belgium No Drawing. Filed Dec. 7, 1967, Ser. No. 688,670 Claims priority, application Great Britain, Mar. 6, 1967, 10,372/67 Int. Cl. G03c 1/34 US. Cl. 96-109 12 Claims ABSTRACT OF THE DISCLOSURE A light-sensitive material comprising a silver halide emulsion layer and containing a mercury(II) chelate of a (poly)amino(poly)carboxylic acid in the form of the acid or a water-soluble salt is described. The chelate exerts a stabilizing and fog-inhibiting action upon the lightsensitive material without causing appreciable desensitization.

This invention relates to improved light-sensitive silver halide emulsions.

Light-sensitive silver halide emulsions are in general characterised by their sensitivity, gradation and fog.

As is well-known, sensitivity, gradation and fog are determined by the way in which the silver halide emulsion is prepared and by the use of special chemical ingredients effecting a desired improvement or result. Addenda to the emulsion, which are of particular im portance for the stability of the light-sensitive characteristics of a silver halide emulsion are the so-called stabilizers.

Stabilizers or antifoggants protect the light-sensitive silver halide emulsions against spontaneous formation and growth of fog known as chemical fog during prolonged storage or storage at high temperatures and humidities or during development to maximum contrast and speed. Indeed, the fog increases with the degree and temperature of development, and, in constant development circumstances, with the time the light-sensitive emulsion is stored and with the temperature and the relative humidity of the atmosphere wherein the emulsion is stored. It is evident that a light-sensitive emulsion should be obtained which is as stable as possible at high temperature and high relative humidity for instance in view of its use in tropical countries.

It is known to protect light-sensitive silver halide emulsions against the growth of chemical fog during storage by addition of stabilizers of the triazolopyrimidine type (azaindolizines). Heterocyclic thioxo and mercapto compounds too have been proposed for this purpose but show the disadvantage of impairing the sensitivity and gradation. The same disadvantageous influence on the sensitivity occurs with the known mercury salts, addition complexes of mercury salts with amines, organic mercury salts and heterocyclic mercury compounds. Indeed, these compounds, when used in the concentration necessary for obtaining a suflicient antifogging action, have a considerable desensitizing eifect.

It is also known that emulsions stabilised with compounds of the triazolopyrimidine type still show a tendency to fog formation in extreme storage circumstances i.e. at very high temperatures and humidities and in extreme development circumstances e.g. rapid processing at elevated temperatures. The addition to these emulsions of the above known mercury compounds reduces the fog ging tendency but, as mentioned above, at the cost of a reduction of the sensitivity.

It has now been founnd that when incorporating in a light-sensitive material comprising a silver halide emulsion layer mercury(II) chelates of (poly)amino-(poly) carboxylic acids, in acid form or in the form of a watersoluble salt, these compounds exert a stabilizing and foginhibiting action upon said photographic light-sensitive material without causing an appreciable desensitization thereof.

Moreover, it has been found that these mercury(II) chelates are very suitable for use in combination with stabilizers of the triazolopyrimidine type, particularly in extreme storage and development circumstances in order to reduce the fogging tendency of the light-sensitive emulsion without giving rise to an appreciable desensitization thereof.

As will be illustrated further on, the mercury(II) chelates of (poly)amino(poly)carboxylic acids can be prepared by allowing to react a water-soluble mercury (II) salt (chloride, cyanide, acetate, etc.) with a (poly) amino(poly)carboxylic acid or water-soluble salt thereof or by treating the sequestering compound, in acid form or in the form of a water-soluble salt, with mercury(II) oX- ide until the mercury oxide has dissolved completely (cf. H. Mohrle, Archiv der Pharmazie 299 (1966) 529).

Examples of suitable (poly)amino(poly)carboxylic acid sequestering compounds for reaction with a mercury (II)salt or mercury(II) oxide to form the corresponding mercury(II) chelates as well as details about the preparation of said sequestering compounds can be found in Ind. Chim. Belg. T XXI (1956), pp. 338-346 and in Ind. Chim. Belg. T XXIII (1958), pp. 1l051115.

Particularly suitable (poly)amino(poly)carboxylic acids for forming in acid or salt form with a mercury(II) salt or mercury(II) oxide the corresponding mercury(II) chelates can be represented by the following non-limitative general formula:

L stands for alkylene including substituted alkylene e.g. hydroxyalkylene, cycloalkylene including substituted cycloalkylene or alkylene interrupted by one or more hetero atoms, such as an oxygen atom,

x represents 0, 1 or 2.

R stands for lower alkylene e.g. methylene and ethylene including substituted lower alkylene, e.g. alkylene substituted by alkyl, aryl, aralkyl, including substituted alkyl, aryl and aralkyl, and

each of R and R (the same or different) stands for hydrogen, lower alkyl including substituted lower alkyl, aralkyl including substituted aralkyl or aryl including substituted aryl; examples of substituted alkyl groups for R and for R are alkyl substituted with hydroxyl, halogen, alkoxy, carbamoyl, amino, substituted amino e.g. dihydroxyalkylamino, epoxy, carboxyl, sulpho, phosphono, mercapto, alkylmercapto, alkoxycarbonyl, a nitrogen-containing heterocyclic ring e.g. pyridyl and examples of substituted aryl groups and aralkyl groups for R and/ or R are: aryl and aralkyl substituted by hydroxyl, halogen, alkyl, alkoxy, nitro, carboxyl and sulpho.

( CH2COOH Q,3-dihydroxypropyl-aminodiacetic acid N- Z-hydroxyethyl) -N-phosphonomelthyl-ethylenediiami11c, N,N-d'iacetic acid N- Q-mercapto-lcai-bgxyethyl -N- 2-hydrnxyethyl) ethyleuedi ahzineflfl'climatic acid HOOC -I-I C CH -OOOH The following preparations illustrate more particularly how the mercuryfll) chelates of the (poly)arnino- (poly)carboxylic acids can be prepared.

PREPARATION 1 Mercury(II) chelate of compound 1 To a solution of 38 g. (0.1 mole) of ethylenediamine N,N,N',N'-tetraacetic acid disodium salt dihydrate in 200 ml. of water 21.5 g. (0.1 mole) of mercury(II) oxide are added portionwise at room temperature with stirring. The mercury(II) oxide dissolves gradually. After 3 hours the aqueous solution obtained is filtered, evaporated under reduced pressure at 50 C. and the solid product formed is dried under reduced pressure at 50 C. in a drying oven. The product obtained is a white amorphous powder which is soluble in water. Yield: 50 g.

PREPARATION 2 Mercury(II) chelate of compound To a solution of 20.9 g. (0.055 mole) of ethyleneglycol bis(2-aminoethyl), N,N,N,N-tetraacetic acid in 400 ml. of water is added at room teemperature a solution of 4.4 g. (0.11 mole) of sodium hydroxide in 50 ml. of water. At the same temperature, 10.8 g. (0.05 mole) of mer cury(II) oxide are then added portionwise with stirring. The mercury(II) oxide dissolves gradually. After 3 hours the aqueous solution obtained is filtered, evaporated under reduced pressure at 50 C. and the solid product formed is dried under reduced pressure at 50 C. in a drying oven. The product obtained is an amorphous powder which is soluble in water. Yield: 31 g.

PREPARATION 3 Mercury(II) chelate of compound 8 To a solution of 43.2 g. (0.11 mole) of diethylenetriamine-N,N,N',N,N"-pentaacetic acid in 400 ml. of water is added at room temperature a solution of 13.2 g. (0.33 mole) of sodium hydroxide in 50 ml. of water. At the same temperature, 21.6 g. (0.1 mole) of mercury(II) oxide are then added portionwise with stirring.

The mercury(II) oxide dissolves gradually. After 3 hours the aqueous solution formed is filtered, evaporated under reduced pressure at 50 C. and the solid product formed is dried under reduced pressure at 50 C. in a drying oven. The product obtained is a white amorphous powder which is soluble in water. Yield: 75 g.

PREPARATION 4 Mercury(II) chelate of compound 4 To a solution of 30.5 g. (0.11 mole) of N-(Z-hydroxyethyl)-ethylenediamine-N,N,N'-triacetic acid in 400 ml. of water is added at room temperature a solution of 4.4 g. (0.11 mole) of sodium hydroxide in 50 ml. of water. At the same temperature, 21.6 g. (0.1 mole) of mercury(II) oxide are then added portionwise with stirring. The mercury(II) oxide dissolves gradually. After 3 hours the aqueous solution obtained is filtered, evaporated under reduced pressure at 50 C. and the solid product formed is dried under reduced pressure at 50 C. in a drying oven. The product obtained is a white amorphous powder which is soluble in water. Yield: 55 g.

PREPARATION 5 Mercury(II) chelate of compound 10 To a solution of 19.8 g. (0.055 mole) of ethylenediamine,N,N'-di(o-hydroxyphenyl-acetic acid) in 400 ml. of water is added at room temperature a solution of 4.4 g. (0.11 mole) of sodium hydroxide in 50 ml. of water. At the same temperature, 10.8 g. (0.05 mole) of mercury(II) oxide are added portionwise with stirring to the brown solution. The mercury(II) oxide dissolves gradually. After 3 hours the aqueous solution obtained is filtered, evaporated under reduced pressure at 50 C. and the solid product formed is dried under reduced pressure at 50 C. in a drying oven. The product obtained is a brown amorphous powder which is soluble in water. Yield: 33 g.

As compared with the known mercury compounds used as stabilizers the mercury(II) chelates according to the present invention when used in the appropriate concentration do not cause or only to a slight extent a decrease in sensitivity.

The antifoggants according to the present invention are particularly suitable for use in combination with compounds which sensitize the emulsion by development acceleration for example compounds of the polyoxyalkylene type such as alkylene oxide condensation products as de scribed among others in US. Pats. 2,531,832 and 2,533,990, in U.K. Pats. 920,637, 940,051, 945,340 and 991,608 and in Belgian Pat. 648,710 and onium derivatives of amino-N-oxides as described in UK. patent application 42,592/ 65.

The stabilizers according to the invention can also be used in combination with other known stabilizers for instance with heterocyclic nitrogen containing thioxo compounds such as benzothiaZoline-2-thione and 1- phenyl-Z-tetrazoline-S-thione, with other mercury compounds and, as said above, preferably with compounds of the hydroxytriazolopyrimidine type (azaindolizines).

The stabilizers according to the present invention may be incorporated into any type of light-sensitive material comprising a silver halide emulsion layer e.g. a spectrally sensitized or non-sensitized emulsion layer, an X-ray emulsion layer, and an emulsion layer sensitive to infrared radiation. They may be incorporated into high-speed negative materials as well as into rather low speed positive materials. Various silver salts may be used as light-sensitive salt e.g. silver bromide, silver iodide, silver chloride, or mixed silver halides e.g. silver chloro-bromide or silver bromo-iodide.

The silver halides are dispersed in the common hydrophilic colloids such as gelatin, casein, zein, polyvinyl alcohol, carboxymethylcellulose, alginic acid, etc., a gelatin being however favoured.

The stabilizing agents are generally incorporated into the silver halide emulsion layer of the light-sensitive material; they may be added to the emulsion during no matter what step of emulsion preparation; however, they are preferably added to the photographic emulsion after chemical ripening and just before coating of the emulsion. The addenda according to the present invention are incorporated into the photographic emulsions according to the methods well known in emulsion preparation, e.g. in the form of a solution in water.

Instead of incorporating the compounds of the invention into the emulsion layer they can also be incorporated into a water-permeable layer e.g. a gelatin covering layer or intermediate layer.

The amount of mercury(II) chelate employed in the light-sensitive silver halide material depends on the particular type of emulsion and the desired eifect and can vary within very wide limits. The optimum amount of mercury(II) chelate to be added can be determined for each particular type of emulsion in a very simple way by application of the usual tests. Usually said compounds are employed in a ratio of about 0.1 mg. to about 30 mg. per mole of silver halide, preferably from 0.5 to 10 mg. per mole of silver halide.

The light-sensitive emulsions may be chemically as well as optically sensitized. They may be chemically sensitized by effecting the ripening in the presence of small amounts of sulphur containing compounds such as allylthiocyanate, allyl thiourea, sodium thiosulphate, etc. The emulsions may also be sensitized by means of 'reductors for instance tin compounds as described in our French patent specification 1,146,955 and in our Belgian patent specification 568,687, imino-amino methane sulphinic acid compounds as described in our British patent specification 789,823 and small amounts of noble metal compounds such as of gold, platinum, palladium, iridium, ruthenium and rhodium.

7 Other addenda such as hardening agents, wetting agents, plasticizers, colour couplers, developing agents and optical sensitizers can be incorporated into the emulsion in the usual way.

The folowing examples illustrate the present invention.

EXAMPLE 1 A high sensitive gelatino silver bromoiodide emulsion (:45 moles percent of iodide) is divided into nine aliquot portions A, B, C, D, E, F, G, H and I.

To each of these emulsion portions, except for one (emulsion A) is added per mole of silver halide one of the following mercury (II) compounds in the amount indicated:

emulsion B: 0.6 l millimole (1.5 mg.) of mercury (II) cyanide emulsion C: 1.2 millimole (3 mg.) of mercury (II) cyanide emulsion D: 0.6 10* millimole (4 mg.) of the mercury (II) chelate of compound 8 trisodium salt emulsion E: 0.6 10- millimole (3 mg.) of the mercury (II) chelate of compound 4 sodium salt emulsion F: 0.6x 10 millimole (3.7 mg.) of the mercury (II) chelate of compound disodium salt emulsion G: 1.2x 10- millimole (7.5 mg.) of the mercury (II) chelate of compound 15 disodium salt emulsion H: 0.6 X 10 millimole (3.1 mg.) of the mercury (II) chelate of compound 1 disodium salt emulsion I: 1.2 10- millimole (6.2 mg.) of the mercury (II) chelate of compound 1 disodium salt.

The nine emulsions are then coated on a subbed cellulose triacetate support and dried whereupon the nine materials thus obtained are stored for 5 days in an atmosphere of 57 C. and 34% of relative humidity.

The stored materials as Well as nine identical freshly prepared materials are exposed and developed for 5 minutes at C. in a developing bath with the following composition:

Water800 ccs. p-Monomethylaminophenol sulphatel.5 g. Sodium sulphite (anhydrous)50 g. Hydroquinone-6 g.

Sodium carbonate (anhydrous)32 g. Potassium bromide-2 g.

Water up to 1000 ccs.

After the treatment in a stop bath, rinsing and fixing of the materials the following sensitometric results are obtained.

Freshly prepared materials Stored materials Relative Relatir e Gradaspeed, Gradaspeed, Material Fog tion percent Fog tion percent 1. 62 100 0. 46 1. 38 118 1. 67 71. 0 l1 1. 51 87 1. 61 33 0 09 l. 61 37 1. 64 89 0.10 1. 61 142 1. 75 89 0 09 1. 71 96 1. 74 94 0. 13 l. 56 145 1. 70 68 0. 09 1. 67 76 1. 48 96 0. 20 1. 54 136 1. 61 61 0. 04 1. 60 74 The speed is given in relative values (i.e. in percent) in respect of the absolute speed of an emulsion to which no mercury (II) compound was added. From this example it clearly appears that for the same fog-level the mercury (II) chelates according to the invention have a markedly less desensitizing eifect than the common organic mercury salts.

EXAMPLE 2 A gelatino silver bromoiodide emulsion (0.20 mole percent of iodide) comprising per mole of silver halide 400 mg. of 5-methyl-7-hydroxy-s-triazolo-[l,5-a]-pyrimidine as stabilizer and per litre of emulsion 1 g. of saponin as coating aid, is divided into 3 aliquot portions.

To emulsion portion B is added 1 mg. of mercury (II) cyanide per mole of silver halide whereas to emulsion portion C 1.5 mg. of the mercury (II) chelate of compound 1 disodium salt is added per mole of silver halide. To emulsion portion A no mercury (II) compound is added.

The three emulsions are coated on a subbed cellulose triacetate support and the emulsion layers are then overcoated with a gelatin antistress layer.

Thereupon the said three materials are developed at 20 C. in a common X-ray developer having the following composition:

Water800 ccs.

p-Monomethylaminophenol hemisulphate4 g. Hydroquinone10 g.

Anhydrous sodium sulphite65 g.

Anhydrous sodium carbonate45 g.

Potassium bromide-5 g.

Water up to 1000 ccs.

The fog produced in the respective materials after a development time of 4 and 8 min. is listed in the following Table 1.

TABLEI Fog produced after a development time of- Material 4 min. 8 min.

Three identical materials A, B and C are kept for 36 hours in an atmosphere of 57 C. and 34% of relative humidity and then developed for 4 min. at 20 C. in the same developer. The fog produced in the respective materials is listed in Table 2.

TABLE 2 Fog produced Material: A

We claim:

1. Photographic material comprising a support and at least one light-sensitive silver halide emulsion layer comprising in said emulsion layer at least one mercury (II) chelate of a (poly)amino(po1y)carboxylic acid in acid form or in the form of a water-soluble salt, said chelate being present in an amount suflicient to stabilize said material with regard to fogging.

2. Photographic light-sensitive silver halide material according to claim 1, wherein said (poly)amino(poly)- carboxylic acid corresponds to the following general formula:

Bi -N L N R'-'G O 0 1'1 x wherein 4. Photographic light-sensitive silver halide material according to claim 1, wherein said material also comprises a hydroxytriazolopyrimidine stabilizer.

5. Photographic light-sensitive silver halide material according to claim 1, wherein said material also comprises a polyoxyalkylene development accelerator.

6. Photographic light-sensitive silver halide material according to claim 1, wherein said emulsion layer is a gelatino silver halide emulsion layer.

7. Photographic material comprising a support and at least one light-sensitive silver halide emulsion layer comprising in a water permeable layer coated at the same side of the support as the emulsion layer at least one mercury (II) chelate of a (poly)amino(poly)carboxylic acid in acid form or in the form of a water-soluble salt, said chelate being present in an amount sufficient to stabilize said material with regard to fogging.

8. Photographic light-sensitive silver halide material according to claim 7, wherein said (poly)amino(poly)- carboxylic acid corresponds to the following general formula:

lower alkyl, aralkyl including substituted aralkyl or aryl including substituted aryl.

9. Photographic light-sensitive silver halide material according to claim 7, wherein said mercury(II) chelate is present in an amount of from 0.1 mg. to 30 mg. per mole of silver halide.

10. Photographic light-sensitive silver halide material according to claim 7, wherein said material also comprises a hydroXytriazolopyrimidine stabilizer.

11. Photographic light-sensitive silver halide material according to claim 7, wherein said material also comprises a polyoxyalkylene development accelerator.

12. Photographic light-sensitive silver halide material according to claim 7, wherein said emulsion layer is a gelatino silver halide emulsion layer.

References Cited UNITED STATES PATENTS 2,273,562 2/1942 Davey et a1. 96109 2,531,832 11/1950 Stanton 9666 2,533,990 12/1950 Blake 96663 2,666,700 1/1954 Balclsiefen 96107 2,751,299 6/1956 Carroll 96l07 3,161,515 12/1964 Welsh 96109 FOREIGN PATENTS 574,802 4/1959 Canada 96l07 WILLIAM D. MARTIN, Primary Examiner T. G. DAVIS, Assistant Examiner U.S. C1.X.R.. 9688, 107 

